Rac1-mediated signaling plays a central role in secretion-dependent platelet aggregation in human blood stimulated by atherosclerotic plaque

Journal of Translational Medicine

Research

Richard Brandl¹  Suman Dwivedi²  Anna L Khandoga²  Wolfgang Siess²  Dharmendra Pandey³ 

[1] Department of Vascular Surgery, Clinic Schwabing, Munich, Germany;Institute for Prevention of Cardiovascular Diseases, University of Munich, Munich, Germany;Institute for Prevention of Cardiovascular Diseases, University of Munich, Munich, Germany;Max-Planck Institute of Biochemistry, Martinsried, Germany;

关键词: Platelet Aggregation;    Atherosclerotic Plaque;    TrioN;    Wall Shear Rate;    Washed Platelet;   

DOI  :  10.1186/1479-5876-8-128

 received in 2010-09-17, accepted in 2010-12-06,  发布年份 2010

来源: Springer

【 摘 要 】

BackgroundPlatelet activation requires rapid remodeling of the actin cytoskeleton which is regulated by small GTP-binding proteins. By using the Rac1-specific inhibitor NSC23766, we have recently found that Rac1 is a central component of a signaling pathway that regulates dephosphorylation and activation of the actin-dynamising protein cofilin, dense and α-granule secretion, and subsequent aggregation of thrombin-stimulated washed platelets.ObjectivesTo study whether NSC23766 inhibits stimulus-induced platelet secretion and aggregation in blood.MethodsHuman platelet aggregation and ATP-secretion were measured in hirudin-anticoagulated blood and platelet-rich plasma (PRP) by using multiple electrode aggregometry and the Lumi-aggregometer. Platelet P-selectin expression was quantified by flow cytometry.ResultsNSC23766 (300 μM) inhibited TRAP-, collagen-, atherosclerotic plaque-, and ADP-induced platelet aggregation in blood by 95.1%, 93.4%, 92.6%, and 70%, respectively. The IC50 values for inhibition of TRAP-, collagen-, and atherosclerotic plaque-, were 50 ± 18 μM, 64 ± 35 μM, and 50 ± 30 μM NSC23766 (mean ± SD, n = 3-7), respectively. In blood containing RGDS to block integrin αIIbβ3-mediated platelet aggregation, NSC23766 (300 μM) completely inhibited P-selectin expression and reduced ATP-secretion after TRAP and collagen stimulation by 73% and 85%, respectively. In ADP-stimulated PRP, NSC23766 almost completely inhibited P-selectin expression, in contrast to aspirin, which was ineffective. Moreover, NSC23766 (300 μM) decreased plaque-stimulated platelet adhesion/aggregate formation under arterial flow conditions (1500s-1) by 72%.ConclusionsRac1-mediated signaling plays a central role in secretion-dependent platelet aggregation in blood stimulated by a wide array of platelet agonists including atherosclerotic plaque. By specifically inhibiting platelet secretion, the pharmacological targeting of Rac1 could be an interesting approach in the development of future antiplatelet drugs.

【 授权许可】

Unknown   
© Dwivedi et al; licensee BioMed Central Ltd. 2010. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.